New Antibiotics Against Resistant BacteriaNaimeh Naseri
A particularly alarming issue in world health today is the rise and prevalence of antibiotic-resistant bacteria, which significantly increases death rates and costs of treatment; and a group of pathogens responsible for the majority of hospital acquired infections – commonly referred to as the ‘ESKAPE’ pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) – have been named as one of the biggest threats to health as a result of their multidrug resistance. On 27 February 2017, WHO published list of bacteria for which new antibiotics are urgently needed. Although the Gram-positive bacteria in the ESKAPE group, including the methicillin-resistant Staphylococcus aureus, have rightly drawn attention over the past decade, infections caused by the Gram-negative microbes have recently been recognized as a more critical healthcare issue. Despite the fact that many Gram-negative bacteria have acquired antibiotic resistance, the pipeline for the development of new antimicrobials that target Gram-negative bacteria remains empty. The dearth of drug candidates against Gram-negative bacteria is attributed to the fact that they might be harder to kill than Gram-positive bacteria, largely due to the presence of an outer membrane (OM) that serves as a highly impermeable barrier, as well as additional defense mechanisms that might be absent in Gram-positive bacteria. Therefore, it is imperative that as these antibiotic-resistant bacteria evolve, so must the medicines that are utilized to treat them.
Nanomaterials are an alternative approach to treating and mitigating infections caused by resistant bacteria. Microbial cells are unlikely to develop resistance to nanomaterials, because they exert toxicity through different mechanisms than conventional antibiotics. For example, as a novel functional nanostructure material, graphene oxide is currently the subject of intense research due to the unique optical, electronic, and mechanical properties that result from its two-dimensional sp2-hybridized carbon structure. As graphene nanostructures have been found to exhibit limited toxicity towards eukaryotic cells, the utilization of graphene oxide for biological applications has been attracting significant attention from the scientific community.
Generally, there are three layers of complexity that are interconnected and need to be considered carefully in the development of graphene oxide for use in biomedical applications: material characteristics; interactions with biological components (tissues, cells, and proteins); and biological activity outcomes. To understand and follow antibacterial mechanisms of this family of nanomaterials, it is critical to know how graphene oxide properties are determinant in their bactericidal performances. The most important factors are the sheets size, concentration, surface area, surface roughness, dispersibility, hydrophilicity and surface functional groups. To know more about fundumentals and details of the subject, some useful review papers are published like: